WO2000007876A1

WO2000007876A1 - An aerofoil having a slat

Info

Publication number: WO2000007876A1
Application number: PCT/GB1999/002574
Authority: WO
Inventors: Michael Thorpe
Original assignee: Bae Systems Plc
Priority date: 1998-08-05
Filing date: 1999-08-03
Publication date: 2000-02-17
Also published as: EP1100719A1; JP2001501895A; GB9816936D0; US6286790B1; CA2339205A1; EP1100719B1; CA2339205C; AU5185399A; BR9912763A

Abstract

The slat (16) is mounted to extend and retract relative to the aerofoil (10) and a data line (28) supported on a mounting cable (20) extends between the slat (16) and the aerofoil (10). The data line (28) is arranged to wrap around the leading edge (12) of the aerofoil (10) in the fully retracted position of the slat (16) and to extend substantially along a straight line between the aerofoil (10) and the slat (16) when the slat is in its fully extended position.

Description

AN AEROFOIL HAVING A SLAT

The invention relates to an aerofoil having a slat mounted to extend and retract relative

to the aerofoil to increase lift especially during landing and take off of an aircraft.

In certain aircraft, it is usual to provide a data link between the slat and the aerofoil to

enable data such as pressure and temperature to be monitored. Known data links

necessitate use of the usual slat mounting track to form a component of the data link.

That involves complexity and considerable expense and an object of the present

invention is to provide an aerofoil having a slat with an improved data link

arrangement.

According to the invention there is provided an aerofoil having a slat mounted to

extend and retract relative to the aerofoil and a data link extending between the slat

and the aerofoil, the data link comprising a line arranged to lie against the aerofoil in

the fully retracted position of slat and to extend across a gap between the aerofoil and

the slat when the slat is in its fully extended position.

By using a simple line as set out above, the cost of providing the data link is reduced

significantly and the data link is far less complex.

Preferably, the line is arranged to wrap around the leading edge of the aerofoil when

the aerofoil is in its fully retracted position. In the preferred embodiment, the line extends substantially along a straight line across

the gap when the slat is in its fully extended position.

By causing the line to wrap around the leading edge of the aerofoil as set out above,

the risk of fretting against the leading edge is minimised. Also, with the line extending

substantially along a straight line between the aerofoil and the slat, the risk of vibration

and significant flapping due to air flow is also substantially minimised.

In use, fluid flow between the aerofoil and the slat preferably causes the line to lie

partially against the rear of the slat and to wrap partially around the leading edge of the

aerofoil where the slat lies between the fully retracted and fully extended positions.

Preferably, the slat moves along a track on the aerofoil and, in such a case, the line is

preferably positioned to one side of the track. In such a case, and where the aerofoil

extends outwardly from a mounting such as an aircraft fuselage, the line is preferably

arranged outboard of the track.

In the preferred embodiment, the line is carried by a support such as a cable anchored

at one end to the aerofoil and at the other end to the slat. Tension in the support is

preferably sufficient to maintain the support line substantially straight but insufficient

to lead to vibration thereof resulting from air flow over the support and the line

thereon when the slat is in its fully extended position. The positioning of anchor

points on the aerofoil and slat for the support is preferably selected such that the shortest distance around the leading edge of the aerofoil between the two anchor points

in the fully retracted position of the slat is substantially the same as the distance in a

straight line between the two anchor points in the fully extended position of the slat.

The aerofoil is preferably a wing of an aircraft.

An aerofoil having a slat in accordance with the invention will now be described by

way of example with reference to the accompanying drawings in which:

Figure 1 is a diagrammatic cross section through part of a leading edge of an aircraft

wing showing the slat in a retracted position;

Figure 1A is a view of part of the leading edge shown in Figure 1 looking in the

direction of arrow A in Figure 1;

Figure 2 is an underside view of part of the slat shown in Figure 1 illustrating a line for

carrying data and a support cable;

Figure 3 is an underplan view of a complete slat for an opposite wing to that shown in

Figure 2;

Figure 4 is a diagrammatic view showing the position of the data line with the slat in

its fully retracted position; Figure 4A is a view on arrow B in Figure 4;

Figure 5 is a view similar to Figure 4 but showing the configuration of the data line

with the slat between its fully retracted and fully extended positions; and

Figure 6 shows the position of the data line where the slat is fully extended.

Looking at Figure 1, a wing 10 has a leading edge 12 ahead of a wing sub-spar 14. A

slat 16 is mounted for movement forwardly and downwardly relative to the wing 10 in

known manner, the slat being mounted for movement on tracks indicated generally at

18 in Figure 3.

A support cable 20 is anchored at 22 to the wing 10 and the opposite end of the

support cable is anchored at 24 to a rear face 26 of the slat 16. The anchors 22, 24

may be in the form of panel fixing screws.

A line 28 for carrying data, for example a tri-axial cable or a number of multi-core

cables or one or more tubes, is secured by suitable attachments 29 to the support cable

20 (see Figures 1A and 3) to cany signals from sensors (not shown) on the slat 16 to a

point 30 on the wing 10. The point 30 is connected to a further line (not shown) which

carries the signals to a suitable processing point on the aircraft. As can be seen from

Figure 1, the data line 28 leaves the support cable 20 adjacent the anchor 24 and

extends downwardly along the rear face 26 of the spar 16 terminating at a connector 36 supported by a bracket (not shown) mounted on the slat 16. Conveniently, that

section of the data line 28 which lies against the rear face 26 of the slat 16 can be taped

against the rear face for security. Alternatively, and as shown in Figure 2, the data line

28 leaves the support cable 20 adjacent the anchor 24 and terminates at an adjacent

connector 37.

The operation of the slat 16 will now be described with reference to Figures 4 to 6.

With the aircraft cruising, the slat 16 is arranged as shown in Figures 4 and 4A which

corresponds to the position shown in Figure 1. In that condition, the data line 28 and

the support cable 20 wrap around the leading edge 12 with sufficient firmness so as to

be resistant to movement resulting from flow of air. In the Figure 4 position, a seal 32

on the slat sealingly contacts the leading edge 12 to prevent air from flowing between

the leading edge 12 and the rear face 26 of the slat 16.

In Figure 5, the slat 16 is shown extended for take off. In that position, the seal 26 has

moved out of contact with the leading edge 12 and air is able to flow between the

leading edge 12 and the rear face 26 of the slat 16. Air flow causes part of the support

cable 20 and data line 28 thereon to wrap around the leading edge 12 and a further part

thereof to lie against the rear face 26 of the slat 16, an intermediate section 34 thereof

being forced by the air stream upwardly into the space between the leading edge 12

and the slat 16. It will be appreciated that the support cable 20 and data line 28 are held firmly in position by the air flow virtually eliminating vibration or other

unwanted movement and, therefore minimising fretting of the leading edge 12.

Figure 6 shows the fully extended position of the slat 16 where the aircraft is landing.

In that position the slat 16 has positioned the anchor 24 relative to the anchor 22 so

that the support cable 20 extends substantially in a straight line between them.

Tension in the support cable 20 is that which results from the weight of the support

cable 20 and the data line 28 thereon and movement of the slat 16 to the Figure 6

position is not intended to pull the support cable 20 tight.

Although the support cable 20 and data line 28 thereon may move slightly as a result

of air flow, the absence of any significant tension effectively prevents the support

cable and data line vibrating. The distance d between the anchors 22, 24 for the

support cable 20 as shown in Figure 6, corresponds substantially to the shortest

distance around the leading edge 12 between the anchors 22, 24 when in the Figure 1

position.

As shown in Figure 3, the mounting cable 20 and data line 28 thereon are positioned

outboard of the respective tracks 18. In that way, the data line 28 is positioned well

clear of the normal slat hack cover (not shown).

Typically, the data line 28 will be used to transmit information from sensors an/or

transducers on the slat 16 for sensing static/dynamic pressures, loading applied to the track, internal or external temperatures etc. Also, the support cable 20 can support a

cable to carry power to the sensors/transducers.

Claims

1 An aerofoil having a slat 16 mounted to extend and retract relative to the

aerofoil 10 and a data link extending between the slat and the aerofoil, the data link

comprising a line 28 arranged to lie against the aerofoil in the fully retracted position

of the slat and to extend across a gap between the aerofoil and the slat when the slat is

in its fully extended position.

2 An aerofoil according to claim 1 in which the line 28 extends substantially on a

straight line across the gap when the slat is in its fully extended position.

3 An aerofoil according to claim 1 or 2 in which the line 28 is arranged to wrap

around at least part of the leading edge 12 of the aerofoil when the slat is in its fully

retracted position.

4 An aerofoil according to claim 3 in which, in use, fluid flow causes the data line

28 to wrap around at least part of the leading edge 12 of the aerofoil where the slat

lies between the fully retracted and fully extended positions.

5 An aerofoil according to any preceding claim in which the data line 28, in use,

lies partially against the underside of the slat 16 where the slat lies between the fully

retracted and fully extended positions. 6 An aerofoil according to claim 5 in which, in use, fluid flow causes the data line

28 to lie partially against the underside of the slat 16 where the slat lies between the

fully retracted and fully extended positions.

7 An aerofoil according to any preceding claim in which the slat 16 moves along

a track 18 on the aerofoil and the data line 28 is positioned to one side of the track.

8 An aerofoil according to claim 7 in which the aerofoil extends outwardly from a

mounting such as an aircraft fuselage and the data line 28 is arranged outboard of the

track 18.

9 An aerofoil according to any preceding claim in which the data line 28 is

carried by a support cable 20 anchored at one end 22 to the aerofoil and at the other

end 36 to the slat.

10 An aerofoil according to claim 9 in which the positioning of anchor points 22,

36 on the aerofoil 10 and slat 16 for the support cable 20 is selected such that the

shortest distance around the leading edge of the aerofoil between the two anchor points

11 An aerofoil according to any preceding claim in the form of an aircraft wing 10. An aircraft having an aerofoil according to any preceding claim.